Conventional paperboard cartons for packaging milk, juice, and other beverage products are typically formed from a paperboard blank assembled in a rectangular open-ended configuration, which is then filled with the liquid contents and sealed with a gable or flat-folded top. The carton forming, filling, and sealing is done under sanitary conditions in lines of "form/fill/seal" machinery. The industry has developed reclosable spouts for such cartons, typically in the form of plastic spout fitments which are sealed to the top end of the cartons. Examples of hinged-type spout fitments are shown in commonly owned U.S. Pat. Nos. 4,705,197 and 4,770,325, both to Gordon and Kalberer. Other types of spout fitments include pull-open nozzles and screw caps. These reclosable spouts allow the cartons to be more easily opened and reclosed without leaking.
The plastic spout fitments are typically attached to the paperboard blanks by sealing a flange portion of the fitment to a heat-sealable coating or extrusion layer on the paperboard, by means of adhesives, heat sealing, or sealing with an ultrasonic horn. The attachment step requires an intermittent certain dwell time for aligning each fitment in position on a carton and applying the required adhesive, heat or ultrasonic energy to the portion to be sealed. An example of indexing machinery for precise registration and sealing of fitments to cartons is shown in commonly owned U.S. Pat. No. 4,846,915 of Keeler et al.
As reclosable spout fitments have come into widespread use, recent developments have been made in fitment sealing apparatus which synchronize the intermittent fitment sealing step with a continuous conveyor line used to supply cartons to form/fill/seal machinery. Examples of such fitment sealing apparatus are shown in commonly owned U.S. Pat. No. 5,102,485 of Keeler and Bombolevich and U.S. Pat. No. 5,100,369 of Keeler. In these examples, the fitments are formed with a flat shape and are supplied to the fitment sealing station from a web or roll.
It is also desirable to apply three-dimensionally shaped spouts, e.g. plastic pull-open nozzles or screw caps, to the cartons at high speed in order to supply a continuous line of fitted cartons to a form/fill/seal machine. One proposal for such an apparatus is shown in U.S. Pat. No. 4,788,811 of Kawajiri et al. This sealing apparatus includes a suction holder which retrieves a three-dimensional cap fitment from the end of a supply chute, moves the fitment axially inside a carton blank assembled in rectangular tube configuration, inserts the spout portion of the fitment laterally through a hole die-cut in the carton wall, and holds the flange portion of the fitment against the heat-sealable coating on the internal side of the carton while an ultrasonic horn is advanced on the external side. This apparatus, however, has the problem that the complex movements required of the cap holder limit the speed at which the machinery can be operated and, further, has a significant risk of mechanical breakdown or misalignment of the fitment.
U.S. Pat. Nos. 4,246,062 and 4,512,136 to Christine disclose apparatus for attaching a fitment to a pouch.
Finally, commonly owned U.S. Pat. No. 5,110,041 to Keeler discloses an apparatus for attaching spout fitments to carton blanks which is integrated in line with conventional form/fill/seal production lines. The spout fitments are attached before the carton blanks are formed, filled and sealed. In accordance with this teaching, dual fitment sealing stations are arranged in line with respective form/fill/seal production lines. Each line requires a continuous input of cartons from the respective station ready to be formed with a bottom end, filled with liquid contents, and sealed at the top end. Each fitment sealing station includes: a carton supply for supplying a series of carton blanks in rectangular tube form, each having the spout hole cut through the carton wall at a selected spout position in the vicinity of the open top end; an indexing conveyor for intermittently advancing the carton blanks in turn to a sealing station; a fitment supply track for supplying a series of fitments to the sealing station through an escapement gate; a fitment retaining mechanism for receiving the fitment released from the escapement gate and positioning it in registration with the spout hole in the carton blank at the sealing station; an anvil movable into the open top end inside the carton adjacent the spout hole position; and a sealing head which is moved to press the fitment in contact with the extrusion layer on the carton wall and against the anvil inside the carton blank. A further support member may be provided between the sealing stations of the two lines to absorb the offsetting impacts of the sealing heads. From the sealing station, the carton fitted with the spout fitment is advanced by the indexing conveyor to an output end where the carton blanks are transferred to the form/fill/seal line. In accordance with one preferred embodiment, the fitments are attached to the carton by application of hot melt adhesive.